1. Field of the Invention
The present invention relates to an eye movement measuring apparatus for measuring eye movement of an eye, an eye movement measuring method, and an recording medium. In specific, the present invention relates to a technique for measuring eye movement based on a fundus oculi image.
2. Description of the Related Art
Conventional techniques for measuring eye movement are disclosed in JP Patent laid-open No. 2005-66358, JP Patent laid-open No. 2005-205024, JP Patent laid-open No. 2005-211329, and JP Patent laid-open No. 2005-323905. The technique disclosed in JP Patent laid-open No. 2005-66358 is to determine the center, radius and a plurality of characteristic regions of an eye based on a moving image of eye movement having been imaged and detecting movement of the eye based on the determination, thereby facilitating the setting of an index for analyzing eye movement.
The technique disclosed in JP Patent laid-open No. 2005-205024 is to irradiate the eyelid of an eye with near-infrared light and measure eye movement based on the intensity of reflection light, thereby improving the sensitivity of measurement of eye movement in a state where the eye is closed.
The technique disclosed in JP Patent laid-open No. 2005-211329 is to improve measurement accuracy, by irradiating the corneal of an eye with light, detecting an image of reflection light of the corneal with a light-detecting part including a plurality of pixels arranged two-dimensionally to generate imaging data showing the amount of incident light for every pixel, and setting the resolution and imaging region in the light-detecting part based on information on movement of a position for the corneal reflection light image to enter the light-detecting part.
In the technique disclosed in JP Patent laid-open No. 2005-323905, a first imaging device for wide-angle imaging of a subject and a second imaging device for imaging the eye of the subject are provided. This technique is to improve measurement accuracy by: calculating control information for controlling the direction of the second imaging device from a picture imaged by the first imaging device; generating a control signal for controlling the direction of the second imaging device by tracing the position of the eye from a picture imaged by the second imaging device; calculating location information of the eye gaze from the picture imaged by the second imaging device; checking a tracing state of the eye in calculation of the location information of the eye gaze; and controlling the direction of the second imaging device by any one of the above control signals based on the results of checking.
As described above, a variety of techniques for measuring eye movement have been developed. In particular, an effort has been put into improvement of measurement accuracy. However, since the amount of movement of an eye during eye movement is extremely small and the moving time is short, it is desired to further improve the measurement accuracy.